Biosensor

Abstract

A biosensor having an electrode layer, which includes a working electrode and a counter electrode, and a reagent layer 10 are formed on an insulating support. Further, a spacer having a long and narrow cut-out portion on the reagent layer is bonded to a cover having an air hole to form a cavity that sucks blood as a liquid sample by capillary phenomenon, and a portion of side walls of the spacer and the cover, which side walls face the cavity, is subjected to a treatment for making the portion itself have hydrophilicity. Accordingly, when blood is sucked into the cavity by capillary phenomenon, the suction is promoted, and the performance of a sensor of the biosensor is improved. Further, the process of manufacturing the sensor is simplified, thereby resulting in increased productivity.

What is claimed is:  
     
       1. A biosensor comprising a cavity into which a liquid sample is drawn by capillary phenomenon, side walls facing the cavity, a support, and electrodes formed on a surface of at least one of said side walls facing the cavity, said electrodes being operable to detect a reaction between the drawn liquid sample and a reagent, and said biosensor being operable to analyze a component in the liquid sample based on the detected reaction, 
       wherein a surface itself of at least a portion of said side walls facing the cavity has hydrophilicity,  
       wherein said side walls facing the cavity are made of a resin material in which a surfactant is mixed by an amount of 0.01 weight % or more of the resin material,  
       wherein the surface of said at least one of said side walls facing the cavity on which said electrodes are formed has hydrophilicity, and  
       wherein a surface of said support is made of a rough surface whose level is 0.001 μm to 1 μm.  
     
     
       2. A biosensor comprising a cavity into which a liquid sample is drawn by capillary phenomenon, side walls facing the cavity, a support, and electrodes formed on a surface of at least one of said side walls facing the cavity, said electrodes being operable to detect a reaction between the drawn liquid sample and a reagent, and said biosensor being operable to analyze a component in the liquid sample based on the detected reaction, 
       wherein a surface itself of at least a portion of said side walls facing the cavity has hydrophilicity,  
       wherein said side walls facing the cavity are made of a film whose surface is covered with a surfactant,  
       wherein the surface of said at least one of said side walls facing the cavity on which said electrodes are formed has hydrophilicity, and  
       wherein a surface of said support is made of a rough surface whose level is 0.001 μm to 1 μm.  
     
     
       3. A biosensor comprising a cavity into which a liquid sample is drawn by capillary phenomenon, and side walls facing the cavity, said biosensor being operable to analyze a component in the liquid sample by a reaction between the drawn liquid sample and a reagent, 
       wherein a surface itself of at least a portion of said side walls facing the cavity has hydrophilicity, and  
       wherein said side walls facing the cavity are made of a film whose surface is covered with a resin having a hydrophilic polar group.  
     
     
       4. A biosensor according to  claim 3 , wherein the thickness of the resin having a hydrophilic polar group which covers the film is at least several tens of angstroms. 
     
     
       5. A biosensor according to  claim 4 , wherein a surface of at least one of said walls on which the reagent that reacts with the drawn liquid sample is formed has hydrophilicity. 
     
     
       6. A biosensor according to  claim 4 , further comprising electrodes formed on a surface of at least one of said side walls facing the cavity, 
       wherein said electrodes are operable to detect the reaction between the drawn liquid sample and the reagent, and  
       wherein the surface of said at least one of said side walls on which said electrodes are formed has hydrophilicity.  
     
     
       7. A biosensor according to  claim 6 , further comprising a support, wherein a surface of said support is made of a rough surface whose level is 0.001 μm to 1 μm. 
     
     
       8. A biosensor according to  claim 3 , wherein a surface of at least one of said side walls on which the reagent that reacts with the drawn liquid sample is formed has hydrophilicity. 
     
     
       9. A biosensor according to  claim 3 , further comprising electrodes formed on a surface of at least one of said side walls facing the cavity, 
       wherein said electrodes are operable to detect the reaction between the drawn liquid sample and the reagent, and  
       wherein the surface of said at least one of said side walls on which said electrodes are formed has hydrophilicity.  
     
     
       10. A biosensor according to  claim 9 , further comprising a support, wherein a surface of said support is made of a rough surface whose level is 0.001 μm to 1 μm. 
     
     
       11. A biosensor comprising a cavity into which a liquid sample is drawn by capillary phenomenon, side walls facing the cavity, a support, and electrodes formed on a surface of at least one of said side walls facing the cavity, said electrodes being operable to detect a reaction between the drawn liquid sample and a reagent, and said biosensor being operable to analyze a component in the liquid sample based on the detected reaction, 
       wherein a surface itself of at least a portion of said side walls facing the cavity has hydrophilicity,  
       wherein a surface of at least a portion of said side walls forming the cavity is chemically reformed,  
       wherein a hydrophilic functional group is formed on a surface of at least a portion of side walls facing the cavity by subjecting the surface on which the hydrophilic functional group is formed to at least one of plasma discharge, coupling reaction, ozone treatment, and UV treatment,  
       wherein the surface of said at least one of said side walls facing the cavity on which said electrodes are formed has hydrophilicity, and  
       wherein a surface of said support is made of a rough surface whose level is 0.001 μm to 1 μm.  
     
     
       12. A biosensor comprising a cavity into which a liquid sample is drawn by capillary phenomenon, side walls facing the cavity, a support, and electrodes formed on a surface of at least one of said side walls facing the cavity, said electrodes being operable to detect a reaction between the drawn liquid sample and a reagent, and said biosensor being operable to analyze a component in the liquid sample based on the detected reaction, 
       wherein a surface itself of at least a portion of said side walls facing the cavity has hydrophilicity,  
       wherein a surface of at least a portion of said side walls forming the cavity is chemically reformed,  
       wherein the surface of said at least one of said side walls facing the cavity on which said electrodes are formed has hydrophilicity, and  
       wherein a surface of said support is made of a rough surface whose level is 0.001 μm to 1 μm.  
     
     
       13. A biosensor comprising a cavity into which a liquid sample is drawn by capillary phenomenon, side walls facing the cavity, a support, and electrodes formed on a surface of at least one of said side walls facing the cavity, said electrodes being operable to detect a reaction between the drawn liquid sample and a reagent, and said biosensor being operable to analyze a component in the liquid sample based on the detected reaction, 
       wherein a surface itself of at least a portion of said side walls facing the cavity has hydrophilicity,  
       wherein the surface of said at least one of said side walls facing the cavity on which said electrodes are formed has hydrophilicity, and  
       wherein a surface of said support is made of a rough surface whose level is 0.001 μm to 1 μm.